The objective of this research is to distinguish different kinds of epidermal cells on the basis of their cell surface glycoproteins. The long-term goal is an understanding of the control mechanisms operative in differentiation and transformation. The epidermal populations that will be compared are differentiated and undifferentiated normal cells (in vivo and in vitro), preneoplastic and neoplastic cells (from established continuous cell lines and from fresh tumor tissue of papillomas and squamous and basal cell carcinomas). Glycoproteins will be characterized by several radioactive labeling techniques (lactoperoxidase-catalyzed iodination, galactose oxidase-borohydride reduction, sodium periodate-borohydride reduction, incorporation of labeled sugars, analysis of labeled glycopeptides, interaction with labeled lectins). Significant glycoproteins will be isolated and used as antigens to prepare specific antibodies. Quantitation with antibodies will utilize rocket immunoelectrophoresis, reaction with antigens on polyacrylamdie gels and radioimmunoassays. Radioimmunoassays will also assess the extent of cell surface shedding in vitro. Retinoids, promoters and interferon alter differentiation and transformation in different ways and have also been shown to affect the cell surface by mechanisms not well understood. We will employ these agents to study their impact on differentiation-related and transformation-related cell surface markers.